2010 Lexus HS250h stop start

24
1-1. Hybrid system
Hybrid system
Your vehicle is a hybrid vehicle. It has characteristics different from con-
ventional vehicles. Be sure you are clos ely familiar
with the characteristics
of your vehicle, and operate with care.
The hybrid system combines the use of a gasoline engine and an electric
motor (
traction motor) according to driving conditions, improving fuel effi -
ciency and reducing exhaust emissions.
Gasoline engine
Electric motor (Traction motor)
■ When stopped/
during start off
The gasoline engine stops* when the v
ehicle is stopped. During
start off, the electric motor (traction motor) drives the vehicle. At
slow speeds or when traveling down a gentle slope, the engine is
stopped* and the motor is used.
When shift position N is selected, the hybrid batter
y (traction bat-
tery) will not be charged. Thus, sele ct P when the v
ehicle is stopped.
In addition, when driving in heavy traffic, use D or B.

25
1-1. Hybrid system
1
Before driving
■Regenerative braking
In the following situations, kinetic energy is converted to electric energy and decel-
eration force can be obtained in conjunction with the recharging of the hybrid bat -
tery (traction battery).
●The accelerator pedal is released while driving with shift position D or B
selected.
●The brake pedal is depressed while driving with shift position D or B selected.
■Conditions in which the gasoline engine may not stop
The gasoline engine starts and
stops automatically. However, it may not stop auto -
matically in the following conditions:
●During gasoline engine warm-up
●During hybrid battery (traction battery) charging
●When the temperature of the hybrid battery (traction battery) is high or low
●When the heater is switched on
*: However, when the hybrid battery (traction battery) need to be
charged or while the engine is being warmed up, the gasoline
engine may not stop automatically.
■ During normal driving
The gasoline engine is predomina ntly used. The electric motor
(tr
action motor) charges the hybrid battery as necessary.
■ When acceler
ating sharply
The power of the hybrid battery (tract ion batter
y) is added to that of
the gasoline engine via the electric motor (traction motor).
■ When br
aking (regenerative braking)
The electric motor (traction motor) char
ges the hybrid battery
(traction battery).

26
1-1. Hybrid system
■Charging the battery
As the gasoline engine charges the hybrid battery (traction battery), the battery
does not need to be charged from an outside source. However, if the vehicle is left
parked for a long time the hybrid battery will slowly discharge. For this reason, be
sure to drive the vehicle at least once every few months for at least 30 minutes or
10 miles (16 km). If the hybrid battery be comes fully discharged and you are unable
to jump-start the vehicle with the 12-v olt battery, contact your Lexus dealer.
■After the 12-volt battery has discharged or has been changed or removed
The gasoline engine may not stop even if the vehicle is running on the hybrid battery
(traction battery). If this continues for a few days, contact your Lexus dealer.
■Sounds and vibrations specific to a hybrid vehicle
There may be no engine sounds or vibrat ion even though the vehicle is able to
move. Always change the shift position to P when parked.
The following sounds or vibrations may occur when the hybrid system is operating
and are not a malfunction:
●Motor sounds may be heard fr om the engine compartment.
●Sounds may be heard from the hybrid ba ttery (traction battery) behind the rear
seats when the hybrid system starts or stops.
●Sounds from the hybrid system may be heard when the trunk lid is open.
●Sounds may be heard from the transaxle wh en the hybrid system starts or stops,
or while the vehicle is idling.
●Engine sounds may be heard when accelerating sharply.
●Sounds may be heard due to regenerati ve braking when the brake pedal is
depressed and accelerator is loosened.
●Other sounds, such as motors and mechanical noises, may be heard from the
brake system when the brake pedal is depressed.
●Vibration may be felt when the gasoline engine starts or stops.
●Cooling fan sounds may be heard from the air intake vent on the side of rear left
seatback.
When driving in Eco mode, the fan noise may be louder than when driving nor-
mally.
■Maintenance, repair, recycling, and disposal
Contact your Lexus dealer regarding main tenance, repair, recycling and disposal.
Do not dispose of the vehicle yourself.

28
1-1. Hybrid system
Hybrid battery air vent
There is an air intake vent on the
side of the rear left seatback for
the purpose of cooling the hybrid
battery (traction battery). If the
vent become blocked, the hybrid
battery may overheat, leading to a
reduction in hybrid battery output.
Emergency shut off system
When a certain level of impact is detected by the impact sensor, the
emergency shut off system blocks off the high voltage current and stops
the fuel pump to minimize the risk of electrocution and fuel leakage. If the
emergency shut off system activates, yo ur vehicle will not restart. To
restart the hybrid system, contact your Lexus dealer.
Hybrid warning message
A message is automatically displayed when a malfunction occurs in the
hybrid system or an improper operation is attempted.
If a warning message is shown on
the multi-information display
, read
the message and follow the
instructions.
( P. 501 )

136
2-1. Driving procedures
Driving the vehicle
The following procedures should be observed to ensure safe driving:
■Starting the hybrid system
 P.
1 4 5
■Driving
With the brake pedal depressed, select the D position. 
( P
. 153) 
Check that the shift position indicator shows D.
Release the parking brake. ( P. 1 6 0 )
Gradually release the brake pedal and gently depress the
accelerator pedal to accelerate the vehicle.
■ Stopping
With the D position illuminated on the shif
t position indicator,
depress the brake pedal.
If necessary, set the parking brake.
If the vehicle will be stopped for an extended period of time, select
the P position. (
P. 1 5 3 )
■ Parking the vehicle
Stop the vehicle by depressing the brake pedal.
Set the parking brake. ( P. 1 6 0)
If parking on a hill, block the wheels as needed.
Press the P position switch to shift into P. ( P. 1 5 4 )
Check that the shift position indicator shows P. ( P. 1 5 3 )
Press the “POWER” switch to stop the hybrid system.
Slowly release the brake pedal and check that the indicator on
the “POWER” switch is off.
Lock the door, making sur
e that you have the electronic key on
your person.

137
2-1. Driving procedures
2
When driving
Starting off on a steep uphill
Make sure that the parking brake is set secu rely, and then select
shift position D. 
Check that the shift position indicator shows D.
Gently depress the accelerator pedal.
Release the parking brake.
■Driving in the rain
●Drive carefully when it is raining, becaus e visibility will be reduced, the windows
may become fogged-up, and the road will be slippery.
●Drive carefully when it starts to rain, be cause the road surface will be especially
slippery.
●Refrain from high speeds when driving on an expressway in the rain, because
there may be a layer of wate r between the tires and the road surface, preventing
the steering and brakes from operating properly.
■Breaking in your new Lexus
To extend the life of the vehicle, observing the following precautions is recom -
mended:
●For the first 186 miles (300 km): 
Avoid sudden stops.
●For the first 994 miles (1600 km):
• Do not drive at extremely high speeds.
• Avoid sudden acceleration.
• Do not drive at a constant speed for extended periods.
■Drum-in-disc type parking brake system
Your vehicle has a drum-in-disc type parking brake system. This type of brake sys -
tem needs bedding-down of the brake shoes perio
dically or whenever the parking
brake shoes and/or drum are replaced. Have your Lexus dealer perform the bed-
ding down operation.

139
2-1. Driving procedures
2
When driving
CAUTION
■When starting the vehicle
Always keep your foot on the brake pedal while stopped with the hybrid system
operating. This prevents the vehicle from creeping.
■When driving the vehicle
●Do not drive if you are unfamiliar with the location of the brake and accelerator
pedals to avoid depressing the wrong pedal.
• Accidentally depressing the accelerator pedal instead of the brake pedal will
result in sudden acceleration that may lead to an accident that could result in
death or serious injury.
• When backing up, you may twist your body around, leading to a difficulty in
operating the pedals. Make sure to operate the pedals properly.
• Make sure to keep a correct driving posture even when moving the vehicle only slightly. This allows you to depress the brake and accelerator pedals
properly.
• Depress the brake pedal using your right foot. Depressing the brake pedal using your left foot may delay response in an emergency, resulting in an acci-
dent.
●The driver should pay extra attention to pedestrians when the vehicle is powered
only by the electric motor (traction motor). Because there is no engine noise, the
pedestrians may misjudge the vehicle’s movement.
●Do not drive the vehicle over or stop the vehicle near flammable materials. 
The exhaust system and exhaust gases can be extremely hot. These hot parts may
cause a fire if there is any flammable material nearby.
●Do not let the vehicle roll backward whil e a forward driving position is selected,
or roll forward while R is selected. 
Doing so may result in an acci dent or damage to the vehicle.
●If the smell of exhaust is noticed inside the vehicle, open the windows and check
that the trunk is closed. Large amounts of exhaust in the vehicle can cause driver
drowsiness and an accident, resulting in death or a serious health hazard. Have
the vehicle inspected by your Lexus dealer immediately.
●Do not shift the shift position to P while the vehicle is moving. 
Doing so can damage the transmission and may result in a loss of vehicle control.
●Do not shift the shift position to R while the vehicle is moving forward. 
Doing so can damage the transmission and may result in a loss of vehicle control.

145
2-1. Driving procedures
2
When driving
Power (ignition) switch
Performing the following operations when carrying the electronic key on
your person starts the hybrid system or changes “POWER” switch modes.
■Starting the hybrid system
Check that the parking brake is set.
Firmly depress the brake pedal.
The “POWER” switch indicator will turn green. If the indicator does
not turn green, the hybrid system cannot be started.
When shift position N is selected, the hybrid system cannot start.
Select the P position when star
ting the hybrid system.
Press the “POWER” switch.
After a while, the “READY” indi -
cator comes on with a beep
sound.
The vehicle can move when the
“READ
Y” indicator is on even if
the engine is stopped.
Continue depressing the brake
pedal
until the hybrid system is
completely started.
The hybrid system can be
star
ted from any mode.